help with Pspice code

I am trying to create the circuit in the link attached (for some reason I couldn't attach images)
http://www.eejournal.ktu.lt/index.php/elt/article/viewFile/1835/1493

page 3 ,figure 3, the parameters are in equ(9) and just above equ(13)

I wrote the following code:

*Fitzhugh Nagumo
I1 0 1 PULSE(0 0.5mA 1NS 1NS 1NS 1NS 2ms)
L1 0 2 30H
R1 1 2 7500ohm
R2 1 0 3174ohm
C1 1 0 16.67nF
G1 1 0 value={-0.000037037*(v(1)**3)+0.00002167*(v(1)**2)}
.tran 0 10ms
.probe
.end

my problem is G1 isn't responding properly (it's giving me 0Amp) (and I think that because of that, also L1 and R1 are not working either)

can someone please help me??